The invention is directed to a monostable electromagnetic rotating armature relay in which two armature legs are connected by means of a ferromagnetic middle member, which armature is cooperable with two laterally opposed yoke arms of an excitation coil which are operative to form working air gaps between the armature legs and respective yoke arms.
Such relays are generally known, as for example German Utility Model No. 1,900,668. However, these known relays require additional external forces for effecting a resetting of the armature. If it is desired to utilize a symmetrical spring contact assembly, such resetting can be effected only by means of additional resetting springs. In addition, such a neutral magnet system is also relatively insensitive.
Further, it has also been proposed to make a polarized rotating armature system monostable, as for example illustrated in German AS No. 2,454,967 and corresponding U.S. Pat. No. 3,993,971. Such a relay utilizes a so-called H-armature having two parallel ferromagnetic bars and at least one intermediate permanent magnet. In order to achieve a monostable switching characteristic, it was proposed that the ferromagnetic bars be staggered by a certain portion of their length, whereby pole surfaces of different size are disposed opposite the pole pieces and armature bars. However, a monostable switching characteristic is still not assured merely by this arrangement. On the contrary, in this arrangement, a monostable characteristic must be induced by additional means, as for example unilaterally mounted separating members and auxiliary springs.